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D. P. WEBSTER.

Battle for Holding Hydrofiuoric Acid.

Patented Apr iI14, 1868.

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- Letters Patent No. 76,678, dated April 14, 186 8.

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TO WHOM IT MAY CONCERN: I

Be it known that I, DAVID P. WEBSTER, of New York, in the county andState of New York, have invented certain new and useful Improvement inthe Preparation of Bottles for Holding Hydrofluoric Acid; and I herebydeclare the following to be a full, clear, and exact description of thesame, reference being had to the accompanying drawing. i i

The bottles now used for holding hydrofluoric acid are either of lead orgutta percha. Both are expensive, the former from the quantity ofmetal'required to impart the stiffness or firmness required, in order totransport or handle the bottles with safety; and the latter, inconsequence of the high price it commands, chiefly for insulatingtelegraph-cable.

- My object is to produce a bottle for this purpose, which, whilepossessing the resistant properties of the lead or gutta percha, shallbe much less expensive than one made of either of the latter materials.To this end,

I form a wooden bottle of well-seasoned wood, in an ordinaryturning-lathe, and thencoat the inside of such bottle with asphalt fromcoal-tar, and the outside with a compound of India rubber and gum-s1 Theshellac and India-rubber mixture is prepared by dissolving, in eightgallons of naphtha, two pounds of India rubber. This solution is addedto double its weight of shellac, and the whole is then placed in an ironI pot, over a gentle heat, and stirned'constantly with aspatula. Whenthe whole is well melted and mixed, the

kettle is removed from the fire, and the mixture poured upon sheets ofzinc, over which it flows; quickly co oling in sheets or plates, whichare broken up for future use;

The wooden bottle, as shown in the accompanying drawing, whichrepresents a vertical central section of said bottle, is formed of twosections A B,.which join at about the base of the arch of the top of thebottle. They are united by means of twovfianges a b, one formed uponeach section, and the one, a, fitting within the other, 6. Thesesections, before being put together, are first lined with the asphalt ofcoal-tar, by melting the asphalt and spreading .it with a brush, or bypouring it into the sections. The no z z'le of the bottle is then coatedon the inside with the compound of shellac and'India rubber, abovereferred to, which, for this purpose, has been previously melted. Thecoating may be put on with a brush or in any other suitable manner.Next, the flanges of the sections are coated with the same compound, andwhile the mixture is still hot and soft, the two sections are pressedtogether, the flange of the one fitting within the flange of the other,where it is tightly held on account of the adhesive character of themixture. The outside of, the bottle is then coated with the compound, byeither dipping the whole bottle in the melted rubber and shellac, or byspreading the same uponit with abrush.

The asphalt may be employed for both sides of the bottle, and so may thecompound of rubber and shellac,

but I prefer the mode I have named above, because the asphalt ischeaper, while the shellac and rubber impart a better appearance to thebottlo,.and distinguish it as designed for hydrofluoric acid; whereas,if the outside coating were of asphalt, the jet-black bottle thusproduced might be easily mistaken for a black glass bottle.

The shape of the bottle I prefor, is that usually given glass bottles,but it is evident that'othcr forms may be employed, for instance, thatof a small keg, and I do not of course desire to confine myself to abottle of any special design or shape. It is evident, also, that insteadof wood, papier-mache may be employed, and other pulpy compounds may beformed into the shape of bottles, and then coated in the manner abovedescribed.

What 'I claim, therefore, and desire to secure by Letters Patent, is

1. The preparation of bottles for receiving hydrofluoric acid, bycoating them internally and externally with asphalt of coal-tar, or thehercin-described composition of gum-shellac and India rubber, as setforth.

- 2. As an article of manufacture, a bottle, made of wood, papicr-machc,or like material, coated externally and internally with a composition orvarnish not aflccted by hydrofluoric acid, substantially as herein shownand set forth.

3. Making the bottle for holding hydrofluoric acid of wood, and in twoparts or sections, united substam tially in the manner and for thepurposes shown and described.

In testimony whereof, I have signed my name to this specification beforetwo subscribing witnesses.

D. I. WEBSTER.

Witnesses M. BAILEY, A. POLLOK.

